Cold Outside? Warm Up With This Animated HTML5 Fireplace
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here's a new interesting html5 tutorial – i will tell you how you can create an attractive html5 canvas fireplace. the main problem is – to draw a live fire on a canvas.
here are our demo and downloadable package:
live demo
download in package
ok, download the source files and let's start coding !
step 1. html
here is the html code of our fireplace page:
index.html
<!doctype html> <html lang="en" > <head> <meta charset="utf-8" /> <title>html5 fire effect | script tutorials</title> <link href="css/main.css" rel="stylesheet" type="text/css" /> <script type="text/javascript" src="js/script.js"></script> </head> <body> <div class="container"> <canvas id="panel" width="370" height="175"></canvas> </div> <footer> <h2>html5 fire effect</h2> <a href="http://www.script-tutorials.com/html5-fire-effect/" class="stuts">back to original tutorial on <span>script tutorials</span></a> </footer> </body> </html>
step 2. css
here are the css styles used:
css/main.css
*{ margin:0; padding:0; } body { background-color:#bababa; color:#fff; font:14px/1.3 arial,sans-serif; background-image: url(../images/bg.jpg); } footer { background-color:#212121; bottom:0; box-shadow: 0 -1px 2px #111111; display:block; height:70px; left:0; position:fixed; width:100%; z-index:100; } footer h2{ font-size:22px; font-weight:normal; left:50%; margin-left:-400px; padding:22px 0; position:absolute; width:540px; } footer a.stuts,a.stuts:visited{ border:none; text-decoration:none; color:#fcfcfc; font-size:14px; left:50%; line-height:31px; margin:23px 0 0 110px; position:absolute; top:0; } footer .stuts span { font-size:22px; font-weight:bold; margin-left:5px; } .container { background-image: url(../images/fireplace.png); bottom:70px; color:#000; height:482px; left: 200px; position:fixed; width:860px; } .container #panel { margin-left: 235px; margin-top: 75px; }
step 3. js
js/script.js
// variables var canvas, ctx; var data_width; var data_height; var colors = []; var out_data = []; // new filled array function function new_filled_array(len, val) { var rv = new array(len); while (--len >= 0) { rv[len] = val; } return rv; } // prepare palette function function prepare_palette() { for (var i = 0; i < 64; ++i) { colors[i + 0] = {r: 0, g: 0, b: i << 1, a: i}; colors[i + 64] = {r: i << 3, g: 0, b: 128 - (i << 2), a: i+64}; colors[i + 128] = {r: 255, g: i << 1, b: 0, a: i+128}; colors[i + 192] = {r: 255, g: 255, b: i << 2, a: i+192}; } } // drawing functions function clear() { // clear canvas function ctx.clearrect(0, 0, ctx.canvas.width, ctx.canvas.height); } function drawscene() { // main drawscene function clear(); // clear canvas var data_cnt = data_width * (data_height - 1); for (var i = 0; i < data_width; i++) { out_data[data_cnt + i] = (0.7 > math.random()) ? 255 : 0; } for (var y = 0; y < 175; y++){ for (var x = 0; x < data_width; x++){ var s = data_cnt + x; var temp_data = out_data[s] + out_data[s + 1] + out_data[s - 1] + out_data[s - data_width]; temp_data >>= 2; if (temp_data > 1){ temp_data -= 1; } temp_data <<= 0; out_data[s - data_width] = temp_data; var id = s << 2; img_data.data[id + 0] = colors[temp_data].r; // red img_data.data[id + 1] = colors[temp_data].g; // green img_data.data[id + 2] = colors[temp_data].b; // blue img_data.data[id + 3] = colors[temp_data].a; // alpha } data_cnt -= data_width; } // draw result data ctx.putimagedata(img_data, 0, 0); } if (window.attachevent) { window.attachevent('onload', main_init); } else { if(window.onload) { var curronload = window.onload; var newonload = function() { curronload(); main_init(); }; window.onload = newonload; } else { window.onload = main_init; } } function main_init() { // creating canvas and context objects canvas = document.getelementbyid('panel'); ctx = canvas.getcontext('2d'); // preparing initial image data (empty) img_data = ctx.createimagedata(canvas.width, canvas.height); data_width = img_data.width, data_height = img_data.height, prepare_palette(); // allocating array with zeros out_data = new_filled_array(data_width * data_height, 0) setinterval(drawscene, 30); // loop drawscene }
most of the code – pure mathematics. you are welcome to spend some time to understand all these processes. i have tried to comment this code as much as possible.
source: http://www.script-tutorials.com/html5-fire-effect/
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